package org.bouncycastle.asn1;

import java.io.IOException;

/**
 * DER IA5String object - this is an ascii string.
 */
public class DERIA5String extends ASN1Object implements DERString {
    String string;

    /**
     * return a IA5 string from the passed in object
     * 
     * @exception IllegalArgumentException
     *                if the object cannot be converted.
     */
    public static DERIA5String getInstance(Object obj) {
        if (obj == null || obj instanceof DERIA5String) {
            return (DERIA5String) obj;
        }

        if (obj instanceof ASN1OctetString) {
            return new DERIA5String(((ASN1OctetString) obj).getOctets());
        }

        if (obj instanceof ASN1TaggedObject) {
            return getInstance(((ASN1TaggedObject) obj).getObject());
        }

        throw new IllegalArgumentException("illegal object in getInstance: " + obj.getClass().getName());
    }

    /**
     * return an IA5 String from a tagged object.
     * 
     * @param obj
     *            the tagged object holding the object we want
     * @param explicit
     *            true if the object is meant to be explicitly tagged false otherwise.
     * @exception IllegalArgumentException
     *                if the tagged object cannot be converted.
     */
    public static DERIA5String getInstance(ASN1TaggedObject obj, boolean explicit) {
        return getInstance(obj.getObject());
    }

    /**
     * basic constructor - with bytes.
     */
    public DERIA5String(byte[] string) {
        char[] cs = new char[string.length];

        for (int i = 0; i != cs.length; i++) {
            cs[i] = (char) (string[i] & 0xff);
        }

        this.string = new String(cs);
    }

    /**
     * basic constructor - without validation.
     */
    public DERIA5String(String string) {
        this(string, false);
    }

    /**
     * Constructor with optional validation.
     * 
     * @param string
     *            the base string to wrap.
     * @param validate
     *            whether or not to check the string.
     * @throws IllegalArgumentException
     *             if validate is true and the string contains characters that should not be in an IA5String.
     */
    public DERIA5String(String string, boolean validate) {
        if (validate && !isIA5String(string)) {
            throw new IllegalArgumentException("string contains illegal characters");
        }

        this.string = string;
    }

    public String getString() {
        return string;
    }

    public String toString() {
        return string;
    }

    public byte[] getOctets() {
        char[] cs = string.toCharArray();
        byte[] bs = new byte[cs.length];

        for (int i = 0; i != cs.length; i++) {
            bs[i] = (byte) cs[i];
        }

        return bs;
    }

    void encode(DEROutputStream out) throws IOException {
        out.writeEncoded(IA5_STRING, this.getOctets());
    }

    public int hashCode() {
        return this.getString().hashCode();
    }

    boolean asn1Equals(DERObject o) {
        if (!(o instanceof DERIA5String)) {
            return false;
        }

        DERIA5String s = (DERIA5String) o;

        return this.getString().equals(s.getString());
    }

    /**
     * return true if the passed in String can be represented without loss as an IA5String, false otherwise.
     * 
     * @return true if in printable set, false otherwise.
     */
    public static boolean isIA5String(String str) {
        for (int i = str.length() - 1; i >= 0; i--) {
            char ch = str.charAt(i);

            if (ch > 0x007f) {
                return false;
            }
        }

        return true;
    }
}
